The present invention relates to a disk control unit and method thereof. More to particularly this invention relates to a disk control unit and method thereof in order to read-out data of a fixed drive.
By way of conventional disk control unit and a method thereof, for instance, in some cases the access for the file is performed continuously, while assuming the sequential access. Further, by way of another conventional disk control unit and a method thereof, the unit learns the preceding access method, and when there is a next access, an access is performed in the same method thereof (referring to the Japanese Patent Application Laid-Open No. HEI 10-124387).
However, in the continuously accessing method of the disk control unit and the method thereof indicated in the conventional example described-above, when the file of a candidate to be accessed is stored non-continuously, there is a problem that performance deteriorates by the fact that the disk control unit fetches unnecessary portion in advance.
Further, in the another conventional disk control unit and the method thereof, the unit learns the preceding access method, and when there is a next access, the access is performed in the same method thereof. A satisfactory performance is indicated about the access on and after the second time, however, there is a problem that the unit can not exercise performance because there is no basis to be learned in the access of the first time.
In view of the foregoing, it is a first object of the present invention, in order to overcome the above-mentioned problem, to provide a disk control unit and a method thereof which enable read-in speed to be improved regarding the file which is stored in a fixed drive discontinuously.
It is a second object of the present invention, to provide a disk control unit and a method thereof which enable data to be fetched in advance, which data corresponds to respective file systems, even though a fixed drive is separated into a plurality of partitions, thus a plurality of file systems are mixed in a plurality of partitions.
According to a first aspect of the present invention, in order to achieve the above-mentioned objects, there is provided a disk control unit which comprises information storage means for storing therein partition information contained in a fixed drive and information of concatenation structure of a file which is contained in the fixed drive, a decode means for decoding information for the sake of prefetch according to both of the partition information stored in the information and the information of concatenation structure of the file, a prefetch means for performing prefetch of data of the fixed drive according to decoded result by the decode means, a prefetch data storage means for storing therein the data which is read-in by the prefetch means temporarily, and a data transmission means for transmitting data which is stored in the prefetch data storage means toward a computer without performing read operation on the fixed drive practically when the data regarding the read-in instruction coincides with the data stored in the prefetch data storage means, in the cases where the read-in instruction is sent from the computer.
According to a second aspect of the present invention, there is provided a disk control unit which is connected to a computer and to a fixed drive, and which is provided with an instruction decode circuit, a partition map, a predictive cache entry, a disk cache, a prefetch program, a prefetch decision circuit, and a disk control circuit, wherein the instruction decode circuit is connected to the computer to decode to be executed the instruction from the computer, the partition map is connected to the instruction decode circuit to maintain a partition information of the fixed drive, the predictive cache entry is connected to the prefetch decision circuit to maintain concatenation state of the file which is contained in the fixed drive, the disk cache is connected to the instruction decode circuit to maintain both of data in which read-in and write occur in the instruction decode circuit, and data which is read-in in the prefetch decision circuit, the prefetch program is connected to the prefetch decision circuit to include decode program in every file system of the prefetch decision circuit, the prefetch decision circuit which is connected to the instruction decode circuit, to the predictive cache entry, and to the disk control circuit, receives read-in instruction which occurs in the instruction decode circuit, thus determining that the read-in instruction belongs to which partition while comparing with the information of the partition map, then presuming that the read-in instruction belongs to which file while comparing with an information of the predictive cache entry, subsequently directing read-in of block portion toward the disk control circuit while determining that the read-in instruction is connected to which block, next storing prefetch data read-in previously in the disk cache, the disk control circuit which is connected to the fixed drive, the instruction decode circuit, and the prefetch decision circuit, receives the read-in data and write instruction from the instruction decode circuit and the instruction from the prefetch decision circuit, thus performing control of the fixed drive, and the instruction decode circuit transmits the prefetch data which is stored in the disk cache toward a computer without performing read operation on the fixed drive practically when the data regarding the read-in instruction coincides with the prefetch data stored in the disk cache, in the cases where the read-in instruction is sent from the computer.
According to a third aspect of the present invention, in the second aspect, there is provided a disk control unit which has a program rewrite means for rewriting the prefetch program according to instruction from the computer.
According to a fourth aspect of the present invention, there is provided a disk control unit which is connected to a computer and to a fixed drive, and which is provided with an instruction decode circuit, a partition map, a predictive cache entry, a disk cache, a prefetch program, a prefetch decision circuit, a RAID data generation circuit, and a RAID disk cache, wherein the instruction decode circuit is connected to the computer to decode to be executed instruction from the computer, the partition map is connected to the instruction decode circuit to maintain a partition information of the fixed drive, the predictive cache entry is connected to the prefetch decision circuit to maintain concatenation state of the file which is contained in the fixed drive, the disk cache is connected to the instruction decode circuit to maintain both of data in which read-in and write occur in the instruction decode circuit, and data being read-in in the prefetch decision circuit, the prefetch program is connected to the prefetch decision circuit to include decode program in every file system of the prefetch decision circuit, the prefetch decision circuit which is connected to the instruction decode circuit, to the predictive cache entry, and to the RAID data generation circuit, receives a read-in instruction which occurs in the instruction decode circuit, thus determining that the read-in instruction belongs to which partition while comparing with the information of the partition map, then presuming that the read-in instruction belongs to which file while comparing with an information of the predictive cache entry, subsequently directing read-in of block portion toward the RAID data generation circuit while determining that the read-in instruction is connected to which block, next storing prefetch data being read-in previously in the disk cache, the RAID data generation circuit which is connected to a plurality of the fixed drives, the instruction decode circuit, and the RAID disk cache, receives the read-in data and write instruction from the instruction decode circuit and the instruction from the prefetch decision circuit, thus performing control of the fixed drive and performing storage and update of the data to the RAID disk cache, the instruction decode circuit transmits the prefetch data which is stored in the disk cache toward a computer without performing the read operation on the fixed drive practically when the data regarding the read-in instruction coincides with the prefetch data stored in the disk cache, in the cases where the read-in instruction is sent from the computer.
According to a fifth aspect of the present invention, in the fourth aspect, there is provided a disk control unit which has a program rewrite means for rewriting the prefetch program according to instruction from the computer.
According to a sixth aspect of the present invention, there is provided a disk control method which comprises the steps of an information storage step for storing both of partition information contained in a fixed drive and information of concatenation structure of a file contained in the fixed drive, a decode step for decoding information for the sake of prefetch according to both of partition information of the information storing means and information of file concatenation structure, a prefetch step for performing prefetch of data of the fixed drive according to decoded result of the decode step, a prefetch data storage step for storing data being read-in by the prefetch step in prefetch data storage means temporarily, and a prefetch data transmission step for transmitting the prefetch data which is stored in the prefetch data storage means toward a computer without performing the read operation on the fixed drive practically when the data regarding the read-in instruction coincides with the prefetch data stored in the prefetch data-storage means, in the cases where the read-in instruction is sent from the computer.
The above and further objects and novel features of the invention will be more fully understood from the following detailed description when the same is read in connection with the accompanying drawings. It should be expressly understood, however, that the drawings are not intended as a definition of the limits of the invention.